Dendrolycopodium obscurum

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Dendrolycopodium obscurum
Lycopodium obscurum.JPG
A mature aerial shoot
Status TNC G5.svg
Secure  (NatureServe)
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Lycophytes
Class: Lycopodiopsida
Order: Lycopodiales
Family: Lycopodiaceae
Genus: Dendrolycopodium
Species:
D. obscurum
Binomial name
Dendrolycopodium obscurum
(L.) A.Haines
Lycopodium obscurum native range.jpg
Native range; also allegedly introduced to Alaska [1]
Synonyms

Lycopodium obscurumL.

Dendrolycopodium obscurum, synonym Lycopodium obscurum, commonly called rare clubmoss, [2] ground pine, [3] or princess pine, [4] is a North American species of clubmoss in the family Lycopodiaceae. [5] It is a close relative of other species such as D. dendroideum and D. hickeyi , also treelike. It is native to the eastern United States and southeastern Canada from Georgia to Minnesota to Nova Scotia. [6] It grows in the understory of temperate coniferous and deciduous forests, where it is involved in seral secondary succession, growing in clonal colonies some years after disturbance has occurred. [7] It has also been found in Japan, Taiwan, Korea, Russian Far East, and northeastern China. [8] [9]

Contents

Description

Dendrolycopodium obscurum is known for the superficial resemblance of its sporophyte to various conifers. However, its above-ground parts are rarely more than 15 cm (6 inches) tall. Its main stem is actually a subterranean, creeping rhizome, which grows about 6 cm (2.4 inches) below ground. Several aerial shoots branch off of the rhizome, which also branch dichotomously several times, giving D. obscurum its distinctive appearance. Fertile shoots possess sessile strobili, borne at the tops of their main axes and sometimes at the tips of dominant lateral branches. The leaves are microphylls, each containing only a single vein and measuring less than 1 cm (0.4 inches) long. Two types of microphylls are formed, green trophophylls that cover most of the aerial shoots, and yellow to tan sporophylls that form the strobili, and contain the sporangia. D. obscurum reproduces sexually via spores and also vegetatively, through its rhizome. [10]

Grove of princess pine.jpg

The gametophyte of D. obscurum is disc shaped prothallus, [11] measuring an average of 1.5 cm (0.6 inches) in diameter. [12] It closely resembles other gametophytes of Lycopodium and related genera, so it cannot be identified by gametophyte alone. Doing so would be difficult nonetheless, as this type of gametophyte grows only underground, years after a disturbance has taken place. [12] Therefore, the compact soil caused by repeated human traffic would disturb these areas, causing D. obscurum spores not to germinate and existing gametophyes to be damaged or killed.

Identification

Closeup of underside of a lateral branch Underside Closeup of lateral branch of L. obscurum.JPG
Closeup of underside of a lateral branch

Identifying D. obscurum in the wild can be difficult without prior study, because it is not only relatively rare, but shares much of its morphology with D. dendroideum and D. hickeyi. However, it can be identified with the naked eye by observing its leaves. Below its first branch, the microphylls of D. obscurum are tightly packed to the axis, while those of D. dendroideum are fully spread down to the soil. [13] The leaves on lateral branches of D. dendroideum and D. hickeyi are evenly shaped and distributed, while they are pressed into the horizontal plane in D. obscurum, with the underside leaves being much shorter than all others. [13]

Growth pattern

Growing in a stand Stand of young shoots.JPG
Growing in a stand

The rhizome of D. obscurum typically produces only one upright shoot per year and grows in a single direction. [14] In the beginning of a growing season, the rhizome grows a few centimeters and then forms one branch at a 90° angle, alternating sides each year, which remains only millimeters in length. It then grows another couple of centimeters and then again branches off to the same side to form an aerial shoot. The rhizome branch produced each year is usually very weak and dies the next, but serves as a reserve rhizome apex, with the potential to become a new main rhizome. [14] This happens if the plant is especially productive, or more frequently if the tip of the main rhizome is damaged so that it cannot grow. When a new main rhizome is formed, it makes a second 90° turn so that it is growing in the same direction as the rhizome from which it came. All underground branching occurs parallel to the ground, so upright shoots must then orient themselves appropriately in order to emerge from the soil. [14]

Every year, a main rhizome produces only one aerial shoot, but in the case of a plant with multiple main rhizomes a new shoot is produced from each. [14] The age of a shoot corresponds to the layers of compressed microphylls in its stem, caused by growth halting each winter, the same way as tree rings are formed. Shoot morphology can also be used to estimate their ages. First year shoots are unbranched and usually do not penetrate the soil surface. Second year shoots undergo rapid growth, usually reaching near their final heights, and forming several systems of lateral branches. [14] Branching occurs only in the second, and sometimes third years. [13] Strobili can be formed as early as the second growing season, but usually begin to be produced in the third. Strobilus production can continue through the fourth year, and shoots die in either the fourth or fifth year. [13]

Taxonomy

The genus Dendrolycopodium is accepted in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), [15] but not in other classifications, which submerge the genus in Lycopodium . [16]

Uses and conservation

Historically, Dendrolycopodium obscurum has been harvested from the wild for use as Christmas greens for wreaths, as well as the use of its spores for flash powder. While flash powder is now practically obsolete, the harvest of D. obscurum has caused it to become threatened in several areas, leading Indiana [1] and New York [3] to declare it protected by state law. When harvesting legally, it is recommended to cut the shoots using shears to minimize rhizome damage, alternate sites every year, and select only individuals possessing strobili with open sporophylls. [7] This ensures that immature shoots are not harvested, and will be allowed an attempt at reproduction.

Related Research Articles

<span class="mw-page-title-main">Lycopodiopsida</span> Class of vascular plants

Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms (Lepidodendrales) formed huge forests that dominated the landscape and contributed to coal deposits.

<span class="mw-page-title-main">Lycopodiaceae</span> Family of vascular plants

The Lycopodiaceae are an old family of vascular plants, including all of the core clubmosses and firmosses, comprising 16 accepted genera and about 400 known species. This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. "Wolf foot" is another common name for this family due to the resemblance of either the roots or branch tips to a wolf's paw.

<i>Lycopodium</i> Genus of vascular plants in the family Lycopodiaceae

Lycopodium is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodium is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted.

<span class="mw-page-title-main">Equisetidae</span> Subclass of ferns

Equisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-like branches radiating at regular intervals from a single vertical stem.

<span class="mw-page-title-main">Sporophyll</span>

A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia and thus are called megasporophylls, or microsporangia and are called microsporophylls. The overlap of the prefixes and roots makes these terms a particularly confusing subset of botanical nomenclature.

<i>Lycopodium clavatum</i> Species of vascular plant in the family Lycopodiaceae

Lycopodium clavatum is the most widespread species in the genus Lycopodium in the clubmoss family.

<i>Lycopodiella</i> Genus of spore-bearing plants

Lycopodiella is a genus in the clubmoss family Lycopodiaceae. The genus members are commonly called bog clubmosses, describing their wetland habitat. The genus has a cosmopolitan distribution, with centers of diversity in the tropical New World and New Guinea. In the past, the genus was often incorporated within the related genus Lycopodium, but was segregated in 1964. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodiella is placed in the subfamily Lycopodielloideae, along with three other genera. In this circumscription, the genus has about 15 species. Other sources use a wider circumscription, in which the genus is equivalent to the Lycopodielloideae of PPG I, in which case about 40 species and hybrids are accepted.

Ground pine or ground-pine may refer to:

A strobilus is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems.

<i>Psilotum complanatum</i> Species of fern in the family Psilotaceae

Psilotum complanatum, the flatfork fern, is a rare herbaceous epiphytic fern ally in the genus Psilotum. There is some evidence that it might be a true fern that has lost some typically fern-like characteristics. Morphologically, the plant is simple, lacking leaves and roots, and having hanging stems with dichotomous branching, which lack developed leaves but have minute scales. The stems and branches have protostele, with a triangular-shaped core of xylem. The scales are arranged in two rows along the flat stems and branches. The stems are broadly triangular in cross section and 5 mm wide. The branches are 1.5 to 2 mm wide. P. complanatum grows 10 to 75 cm long and stems branch in pairs a number of times up their length and are covered with brownish colored hair-like rhizoids. Small stalks end with simple sporangia from the axils of minute bifid, rounded sporophylls. Bean shaped, monolete spores are produced. The spores germinate best in a dark environment when ammonium is present. The gametophyte is non-photosynthetic, living in association with a fungus for its nutritional needs. Plants grow from a subterranean rhizome which anchors the plant in place and absorbs nutrients by means of filament like rhizoids.

<i>Phlegmariurus phlegmaria</i> Species of fern

Phlegmariurus phlegmaria, synonym Huperzia phlegmaria, commonly known as either coarse tassel fern or common tassel fern, is an epiphytic species native to rainforests in Madagascar, some islands in the Indian Ocean, Asia, Australasia and many Pacific Islands. Phlegmariurus phlegmaria is commonly found in moist forests and rainforests at high altitudes, in and amongst mosses and other epiphytes. Members of the order Lycopodiales are commonly referred to as clubmosses.

<i>Selaginella apoda</i> Species of spore-bearing plant

Selaginella apoda, commonly known as meadow spikemoss, is a perennial lycophyte native to much of the eastern United States and parts of northeastern Mexico. The life cycle is the shortest of the genus Selaginella, as well as one of the shortest among the lycophytes. Selaginella apoda is found primarily in damp soils in habitats such as swamps, wet fields, open woods and along stream banks. Selaginella apoda presents the potential for case studies involving the plant's adaptability to environmental toxins. A lowland plant, it has only been recorded at elevations below 100 meters. It is closely related to Selaginella eclipes and S. ludoviciana, with both of which it has been reported to form hybrids. This group is characterized by relatively flat strobili and large megasporophylls which occur in the same plane as the lateral leaves.

<i>Dendrolycopodium dendroideum</i> Species of spore-bearing plant

Dendrolycopodium dendroideum, synonym Lycopodium dendroideum, known as tree groundpine, is a North American species of clubmoss. It is part of a complex of species colloquially known as groundpine, which taxa were formerly lumped into the species Lycopodium obscurum. The species is native to Russia and also to the colder parts of North America. The genus Dendrolycopodium is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not in other classifications, which submerge the genus in Lycopodium.

<i>Diphasiastrum digitatum</i> Species of plant

Diphasiastrum digitatum is known as groundcedar, running cedar or crowsfoot, along with other members of its genus, but the common name fan clubmoss can be used to refer to it specifically. It is the most common species of Diphasiastrum in North America. It is a type of plant known as a clubmoss, which is within one of the three main divisions of living vascular plants. It was formerly included in the superspecies Diphasiastrum complanatum. For many years, this species was known as Lycopodium flabelliforme or Lycopodium digitatum.

<i>Dendrolycopodium</i> Genus of spore-bearing plants

The genus Dendrolycopodium is a clubmoss genus in the family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium. It is treated as section Obscura when retained within Lycopodium. The genus includes a discrete group of plants with similar morphologies. All have erect to semi-erect, branched stems.

<i>Diphasiastrum tristachyum</i> Species of spore-bearing plant

Diphasiastrum tristachyum, commonly known as blue clubmoss, blue ground-cedar, ground pine, deep-rooted running-pine or ground cedar, is a North American and Eurasian species of clubmoss. In North America, it has been found from Newfoundland west to Manitoba, and south as far as Georgia and Alabama. In Eurasia, it ranges from southern Norway and Sweden south to France and Italy and it also occurs in the Caucasus.

<i>Dendrolycopodium hickeyi</i> Species of spore-bearing plant

Dendrolycopodium hickeyi known as Hickey's tree club-moss or Pennsylvania clubmoss, is a North American species of clubmoss in the family Lycopodiaceae. It is native to eastern and Central Canada and the eastern and north-central United States. The genus Dendrolycopodium is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not in other classifications, which submerge the genus in a larger Lycopodium.

<i>Lycopodiella alopecuroides</i> Species of spore-bearing plant

Lycopodiella alopecuroides, the foxtail clubmoss, is a species of perennial vascular plant in the club-moss family, Lycopodiaceae. It is commonly found along the Atlantic seaboard and has been recently been discovered in the state of Maine. The family, Lycopodiaceae contains nearly 15 genera and about 375 species

<span class="mw-page-title-main">Lycopodioideae</span> Subfamily of spore-bearing plants

Lycopodioideae is a subfamily in the family Lycopodiaceae in the Pteridophyte Phylogeny Group classification of 2016. It is equivalent to a broad circumscription of the genus Lycopodium in other classifications. Like all lycophytes, members of the Lycopodioideae reproduce by spores. The oldest fossils of modern members of the subfamily date to the Early Cretaceous.

<span class="mw-page-title-main">Lycopodielloideae</span> Subfamily of plants

Lycopodielloideae is a subfamily in the family Lycopodiaceae in the Pteridophyte Phylogeny Group classification of 2016. It is equivalent to a broad circumscription of the genus Lycopodiella in other classifications. Like all lycophytes, members of the Lycopodielloideae are vascular plants that reproduce by spores.

References

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  2. USDA, NRCS (n.d.). "Lycopodium obscurum". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 24 June 2015.
  3. 1 2 Department of Environmental Conservation. 2000. Protected native plants. Division of Land and Forests, New York.
  4. Native Plant Trust GoBotany. 2020. Dendrolycopodium obscurum (L.) A. Haines flat-branched tree-clubmoss. Native Pangt Trust, Framingham, Massachusetts USA.
  5. Merritt Lyndon Fernald. 1954. Gray's Manual of Botany A Handbook of the Flowering Plants and Ferns of the Central and Northeastern United States and Adjacent Canada.
  6. Biota of North America Program 2014 county distribution map, Dendrolycopodium obscurum
  7. 1 2 Nauertz, Elizabeth A. and Zasada, John C. 2000. Lycopodium: Growth Form, Morphology, and Sustainability of a Non-timber Forest Product. General Technical Report - North Central Research Station, United States Department of Agriculture National Forest Service. pp. 110-115.
  8. Family Lycopodiaceae, genus Lycopodium; world species list
  9. Flora of China, Lycopodium obscurum Linnaeus, 1753. 玉柏 yu bai
  10. Flora of North America, Lycopodium obscurum Linnaeus, 1753.
  11. Bruce, James G. and Beitel, Joseph M. 1979. A Community of Lycopodium Gametophytes in Michigan. American Fern Journal. 69:2. pp. 33-41.
  12. 1 2 Whittier, Dean P. 1977. Gametophytes of Lycopodium obscurum as grown in axenic culture. Canadian Journal of Botany. 55. pp. 563-567.
  13. 1 2 3 4 Hickey, R. James. 1977. The Lycopodium obscurum Complex in North America. American Fern Journal. 67:2. pp. 45-48.
  14. 1 2 3 4 5 Primack, Richard B. 1973. Growth Patterns of Five Species of Lycopodium. American Fern Journal. 63:1. pp. 3-7.
  15. PPG I (2016). "A community-derived classification for extant lycophytes and ferns". Journal of Systematics and Evolution. 54 (6): 563–603. doi: 10.1111/jse.12229 . S2CID   39980610.
  16. Christenhusz, Maarten J.M. & Chase, Mark W. (2014). "Trends and concepts in fern classification". Annals of Botany. 113 (9): 571–594. doi:10.1093/aob/mct299. PMC   3936591 . PMID   24532607.